WO1999060359A1 - Pressure sensor and door opening/closure monitoring system - Google Patents

Abstract

A pressure sensor (10) has a sensor chip (14) in a package (13) structured by joining the open side of a stem (11) to the open side of a cap (12). Exerted on both side of a diaphragm (14a) of the sensor chip are pressures transmitted through a measurement pressure introducing pipe (11a) provided to the stem and a reference pressure introducing pipe (12a) provided to the cap. In the reference pressure introducing pipe, a filter (15) is provided to retard the pressure response on the reference pressure side. This sensor is installed in a room with a door, and the room pressure is supplied through the pipes. When the door is opened or closed, a sudden pressure change is produced. Such a sudden pressure change is instantly transmitted only through the pipe which has a quick pressure response, and a differential pressure corresponding to the pressure change is exerted on the diaphragm. Since the differential pressure is thus used, it is possible to distinguish the opening of the door from the closure.

Description

 Description Pressure sensor and door opening / closing monitoring system

 The present invention relates to a pressure sensor and a door opening / closing monitoring system, and more specifically, to a sensor suitable for detecting opening / closing of a door. Background art

 There are various types of sensors for detecting the opening and closing of the door, such as a switch type, an optical type, and an infrared ray type. Both types of sensors monitor the state and position of the door to be detected in a straight line, and have limitations such as the fact that they must be installed near the door. In addition, since it is easy for a third party to detect that the sensor has been installed, it is easy to take countermeasures when using it in a hairpin system that detects an intruder. In addition, since only one door can be detected by one sensor, to detect the opening and closing of multiple doors, sensors are required as many as the number of doors.

 On the other hand, in order to solve such a problem, a sensor for detecting the opening / closing of the door based on a pressure change caused by the opening / closing of the door is disclosed in, for example, Japanese Utility Model Registration No. 03039782. It is disclosed as a "sensor for an independent hairpin system." A system using the system is disclosed in Utility Model Registration No. 039783 as a “self-control system”.

As shown in FIG. 1A, the sensor disclosed in the publication has an opening 1 a at a negative end of a cylindrical casing 1, and a screen 3 that becomes a pressure receiving surface in the casing 1 in order from the opening 1 a side. , A counter electrode 4 and an amplifier circuit 5. Further, a partition wall 6 having a through hole 6a is provided on the back side of the casing 1, and a chamber 17 is formed between the partition wall 6 and the back surface of the casing 1, whereby a differential differential pressure gauge is provided. Is composed. When the pressure in the installed space fluctuates, this sensor senses the change on the pressure receiving surface and outputs the voltage as shown in Fig. 1B as the sensor output. Thus, for example, if the door does not open and close and the indoor air pressure is constant, the sensor output does not change (the reference level remains), and if the indoor air pressure changes due to the opening and closing of the door, Since the sensor output changes, it is possible to detect the presence or absence of opening and closing. The “self-maintenance system” of Utility Model Registration No. 0397783 installs the above-mentioned sensor and one infrared sensor in the room one by one, and mainly uses the output of the differential differential pressure sensor. To monitor the opening and closing of the door.

 However, the above-mentioned conventional sensor (utility model registration No. 0397782) is large because it is a mechanical type. Moreover, since the pressure change due to the actual opening and closing of the door is very small, it is necessary to increase the detection sensitivity of the sensor. In order to increase the detection sensitivity, the ratio between the depth L of the casing 1 and the depth t of the chamber 17 must be increased, so that the size and shape of the sensor are further increased.

 Also, because it is a differential differential pressure gauge, it can only determine the presence or absence of a change in pressure, and cannot determine whether the door is open or closed.

 Furthermore, the self-security system cannot determine which door is open when there are multiple doors in the room. Also, if the sensor itself breaks down, the sensor output remains at the reference level, and it is determined that there is no intruder. In other words, there are various problems such as a lack of a function for detecting a sensor failure.

 The present invention has been made in view of the above background. It is an object of the present invention to solve the above-described problem, to detect the opening and closing of a door with small size and high sensitivity, and to determine whether the door is opened or closed. The operation status of the sensor can be recognized, the installation position of the sensor is less restricted, and it is difficult to find out from the outside that the sensor is installed. In addition, when there are multiple doors, which door is An object of the present invention is to provide a pressure sensor and a door open / close monitoring system capable of determining whether the door has been opened or closed. Disclosure of the invention

In order to achieve the above object, in a pressure sensor according to the present invention, a pressure sensor for detecting a pressure difference between a pressure receiving side and a reference pressure side includes a pressure response between the pressure receiving side and the reference pressure side. The gender was configured to be different. This pressure sensor is realized by, for example, a semiconductor pressure sensor having a diaphragm that is displaced by pressure. The pressure receiving side is a side to which the pressure to be measured is applied in a normal pressure sensor.

 In this way, the pressure responsiveness differs between the pressure receiving side and the reference side. Therefore, if the response (response speed) is rapid, the sudden pressure change caused by opening and closing the door, etc., is instantaneously detected by the pressure sensor. Although the pressure can be transmitted to the pressure section, if the response is slow, the pressure change cannot be transmitted instantaneously. As a result, a shift occurs in the transmission speed of the rapid pressure change between the pressure receiving side and the reference pressure side, and a differential pressure is applied. Therefore, the pressure change accompanying the opening and closing of the door becomes the above-mentioned differential pressure and is detected by the pressure sensor.

 On the other hand, when the pressure changes slowly, for example, due to a change in temperature or a change in the atmospheric pressure, even if there is a difference in responsiveness, the time when the pressure is finally transmitted to the pressure sensing part of the pressure sensor Are the same and there is no differential pressure. Therefore, the sensor output changes only in response to a sudden pressure change such as opening and closing of the door, so that the opening and closing of the door can be easily detected. In addition, by utilizing the difference in pressure response speed, high sensitivity can be achieved even with a small size. In addition, the direction of pressure change is different when the door is open and when it is closed. In the present invention, since the differential pressure is detected, it is possible to discriminate whether the pressure has increased or decreased. Therefore, it is possible to recognize the operation state of opening and closing the door, more specifically, the operation state of the door being opened and closed.

 In addition, since a change in pressure (differential pressure) is detected, it is not always necessary to install it around the door, which not only increases the degree of freedom in layout, but also does not directly monitor the operation of the door. Screens' Can be hidden behind partition walls. Furthermore, one sensor can detect the opening and closing of multiple doors. When determining which of the plurality of doors has been opened or closed, it is necessary to prepare a plurality of sensors as described in claim 6.

Various measures can be considered as a device for making the pressure responsiveness different, but as an example, the device may be a filter provided at least on the reference pressure side and serving as a gas passage resistance. it can. This is realized in the first embodiment. Further, as another device, a closed space forming member (corresponding to the container 16 in the embodiment) provided on the reference pressure side can be used. This closed space forming member constitutes a sensor. It may be formed on a semiconductor, or may be externally attached as in the embodiment. Further, it is more preferable to make a minute hole in the closed space forming member. This is achieved in the second embodiment. Also, the formation of the closed space with minute holes in this manner also has a secondary effect that the clogging of the reference pressure side due to dirt and dust can be suppressed as much as possible.

 On the other hand, the pressure receiving side detects the pressure in the room having the door, and the reference pressure side applies the same pressure as the pressure in the room, so that the pressure responsiveness between the pressure receiving side and the reference pressure side can be improved. The difference may be used to detect a pressure change due to the opening and closing of the door. In order to apply a pressure equal to the indoor pressure to the reference pressure side, for example, when the indoor air pressure is equal to the outdoor air pressure, the reference side may be introduced from the outdoor. Of course, the pressure in the room may be applied in the same way as the pressure receiving side. In other words, “equivalent” here is a concept that includes “identical”.

 Further, in the door opening / closing monitoring system according to the present invention, a plurality of pressure sensors for detecting a pressure difference between the pressure receiving side and the reference pressure side provided with a device for making the pressure responsiveness different between the pressure receiving side and the reference pressure side are prepared. In addition, a determiner that installs the plurality of pressure sensors in a room having a plurality of doors to be monitored and determines which door has been opened or closed based on a difference between sensor outputs of the plurality of pressure sensors (in the embodiment, (Corresponding to the comprehensive judgment unit 30).

In this way, it is possible to determine which door is open or closed by using a plurality of sensors. In other words, the distance between the sensor installation position and the door is different, and there is a time lag in transmitting the pressure change accompanying the opening and closing of the door to the sensor installation position. Therefore, the opened / closed door can be specified based on which of the plurality of sensors detects the pressure change first. In addition, the time lag of detection by each sensor indicates the distance to the source of pressure change, that is, the door that has been opened and closed.By installing at least two sensors, not only three sensors as in the embodiment, but also For these doors, it is possible to identify which door has been opened or closed. BRIEF DESCRIPTION OF THE FIGURES 1A and 1B show a conventional door open / close detection sensor.

 FIG. 2 is a view showing a pressure sensor according to the first embodiment of the present invention.

 3A and 3B are diagrams showing an example of use of the pressure sensor according to the first embodiment.

 FIG. 4 is a diagram showing a pressure sensor according to a second embodiment of the present invention.

 FIG. 5 is a diagram showing a signal processing circuit.

 FIG. 6 is a diagram showing a configuration of the magnification determining unit.

 FIG. 7 is a diagram showing a configuration of the learning unit.

 FIG. 8 is a diagram illustrating a configuration of the determination unit.

 FIG. 9 is a diagram showing the configuration of the output unit.

 FIG. 10 is a diagram showing the configuration of the setting unit.

 FIG. 11 is a diagram showing an example of an installation state of the door opening / closing monitoring system according to the present invention. Fig. 12A, 12B, Fig. 13, Fig. 14, and Fig. 15 are diagrams explaining the operation principle of the door opening / closing monitoring system.

 FIG. 16 is a diagram showing another example of the installation state of the door opening / closing monitoring system according to the present invention.

 FIG. 17 is a block diagram of the door opening / closing monitoring system according to the present invention. BEST MODE FOR CARRYING OUT THE INVENTION

 Hereinafter, embodiments of the present invention will be described with reference to the drawings.

Referring to FIG. 2, a pressure sensor 10 according to a first embodiment of the present invention includes a package 13 in which a stem 11 and a cap 12 are joined to each other on their open surfaces. It has a basic configuration in which a sensor chip 14 is attached to the sensor. That is, the sensor chip 14 is formed of a semiconductor sensor having a diaphragm 14a which bends under pressure. In this example, a piezo element or the like is attached to the periphery of the diaphragm 14a, and the displacement amount of the diaphragm 14a and the measurement object are determined based on the resistance value of the piezo element that deforms following the displacement of the diaphragm 14a. Pressure is being detected. Of course, the present invention is not limited to this type. For example, a fixed substrate such as a glass substrate may be further provided to provide a capacitance type sensor, or various other types may be used. Then, the sensor chip 14 is attached to the bottom surface of the stem 11. The stem 11 has a through hole in the center of the bottom surface, and a pressure receiving (measurement pressure) force introduction pipe 11a continuous to the through hole in the center of the bottom surface. As a result, the pressure introduced through the measurement pressure introduction pipe 11a impinges on the diaphragm 14a.

 In addition, a through hole is provided at the center of the top surface of the cap 12, and a reference pressure introducing pipe 12a continuous with the through hole is provided at the center of the outside of the top surface. As a result, the reference pressure introduced via the reference pressure introduction pipe 12a hits the opposite surface of the diaphragm 14a.

 As a result, the measured pressure (receiving pressure) and the reference pressure are applied to both surfaces of the diaphragm 14a, so that the diaphragm 14a is displaced by an amount corresponding to the pressure difference. That is, the pressure sensor according to the present invention has a basic structure of a differential pressure gauge that compares a measured pressure with a reference pressure and obtains an output according to the difference.

 Here, in the present embodiment, the responsiveness / response speed differs between the measured pressure side and the reference pressure side with respect to the pressure change. Specifically, this is achieved by installing a filter 15 in the reference pressure introduction pipe 12a. The filter 15 may be made of, for example, a porous material or may be made like an orifice.

 With this configuration, the pressure of the indoor air is transmitted to the sensor chip 14 as air after passing through the filter 15. Since the filter 15 does not transmit a steep change in pressure but transmits a gradual change, when the pressure in the room changes rapidly due to opening and closing of a door, etc., the diaphragm 14 of the sensor chip 14 a The response speed of pressure change is different on both sides (measurement pressure side and reference pressure side), and a signal corresponding to this difference appears as a sensor output. On the other hand, in the case of a gradual pressure change such as a temperature change or a change in the atmospheric pressure, the change is transmitted irrespective of the presence or absence of the filter 15, so that a balance can be obtained on both sides of the diaphragm 14a. That is, there is no change in the sensor output, and the influence on the environmental change can be suppressed as much as possible.

Next, a specific example of use will be described. As shown in FIG. 3A, a pressure sensor 10 is installed at a predetermined position in a room 17 to be monitored. This installation position does not necessarily have to be near the door 18, but can be arranged away from the door as shown in the figure. Alternatively, a position that is not directly opposed to the door 18 such as the back side of the partition wall 19 may be used. This This makes it difficult for an intruder or the like from outside to know the presence of the pressure sensor 10, so that mischief with respect to the pressure sensor 10 can be prevented and detection can be performed more reliably. Further, the measurement pressure introducing pipe of the pressure sensor 10 and the reference pressure introducing pipe are both installed so as to introduce the air in the room 17 into the inside.

 With this configuration, the opening and closing of the door 18 can be detected according to the following measurement principle. In other words, as shown in the figure, in the case of the type that opens and rotates toward the outside of the room 17 as shown in the figure, if the door 18 is closed while the door 18 shown in the figure is open, the door 1 The air around 8 begins to flow into the room, and the air pressure in room 17 temporarily rises. Conversely, when the door 18 is opened from the closed state, the air around the door 18 follows the rotation of the door 18 and is discharged out of the room 18. As a result, the internal pressure of the room 17 decreases. Of course, if there is no pressure difference between the inside and outside of the room 18, then the outflowing air returns to the inside of the room, and once the pressure rises, the air becomes equilibrium.

 As described above, the opening and closing of the door 18 changes the pressure in the room 17, and the direction of the pressure change (elevation) is reversed. Therefore, as shown in Fig. 3 (B), the sensor output also has a waveform as the door opens and closes, and the direction of the projection is reversed between "close" and "open". Therefore, based on the sensor output, the presence or absence of opening / closing and the operation of either can be identified.

 FIG. 4 shows a second embodiment of the pressure sensor according to the present invention. Since the basic sensor structure is the same as that of the first embodiment shown in FIG. 2, the same reference numerals are given and the detailed description is omitted.

 Here, in this embodiment, a buffer space (closed space) is provided in place of the filter 15 as a structure for making the response to the pressure change different between the measurement pressure side and the reference pressure side. That is, the container 16 is attached to the reference pressure introduction pipe 12a. The container 16 has a main body 16a having a space with a relatively large internal volume, and has a small hole 16b formed on a side surface of the main body 16a, and is formed on the opposite side to the small hole 16b. The connection pipe 16c is connected to the reference pressure introduction pipe 12a.

As a result, the diaphragm 14a of the sensor chip 14 is opened to the atmosphere through the minute hole 16b, the main body 16a, the connecting pipe 16c, and the reference pressure introducing pipe 12a. You. Since the space of the main body 16a has a very large volume with respect to the micropores 16b, the micropores 16b and the space inside the main body 16a serve as an electric resistor and a capacitor. Play a part. That is, a steep pressure change such as a door opening / closing is directly transmitted to the sensor chip 14 via the measuring pressure introducing pipe 11a on the measuring pressure side. On the other hand, on the reference pressure side, it passes through the microhole 16b and is transmitted to the sensor chip 14 via the main body 16a (space) and the reference pressure introducing pipe 12a. Therefore, there is a difference between the time when the pressure spreads in the space through the minute hole 16b and the time of the steep pressure change due to the opening and closing of the door, and the pressure change is instantaneously transmitted to the reference side of the diaphragm 14a. Not done. Therefore, from the difference in response speed, the pressure at the reference side of the diaphragm 14a remains at the pressure before the door opens or closes, or the pressure almost equal to the pressure before the door opens and closes. The pressure difference from the applied pressure is applied to the diaphragm 14 a of the sensor chip 14. Therefore, opening and closing of the door can be detected according to the same principle as in the first embodiment.

 Next, a signal processing circuit for detecting the actual opening / closing of the door using the above-described pressure sensor will be described. As shown in FIG. 5, the signal processing circuit 20 receives the output of the pressure sensor 10 and performs predetermined signal processing.In this embodiment, a monitoring mode for detecting actual opening and closing is provided. A learning mode is provided to generate the criteria (knowledge) for monitoring in the monitoring mode.

 First, after the output of the pressure sensor 10 is amplified by the amplifier 21, unnecessary frequency components are removed by the filter 22 and converted to digital signals by the A / D converter 23. It has become. Then, the converted digital signal is sent to the contact switch 25 via the magnification determining unit 24, and is sent to the learning unit 26 or the judgment unit 27 which is selected alternatively. I have. Then, the processing result of the learning unit 26 or the determination unit 27 is sent to the output unit 28, and is output in a predetermined mode. Further, the switching command / setting command for each processing unit is performed based on a control signal from the setting unit 29. The specific structure of each of the processing units described above is as follows.

The amplification unit 21 amplifies the signal level of the sensor output to a level that can be processed. The amplification factor is determined by the magnification determination unit 24, and is based on the control signal sent from the magnification determination unit 24. Is set. Specifically, amplifying unit 2 1 The ratio of the resistance that determines the magnification of the amplifier is selected, and set to a value such that the signal amplified by the amplifier 21 falls within the input range (or output range) of the AZD converter 23. That is, if the peak value of the waveform exceeds the input range, the gain is reduced, and if the peak value is below the input range or extremely small, the gain is set to increase.

 The filter unit 22 removes unnecessary frequency components of the amplified signal that are not necessary for determination, and includes a series connection of a high-pass filter for removing low-frequency components and a single-pass filter for removing high-frequency components. Is installed. The cutoff frequency should be such that the DC component of the signal can be removed in the case of a high-pass filter (for example, 1 Hz or less). Frequency band (for example, about 1 kHz). The setting of the cutoff frequency is performed by the setting unit 29.

 The AZD converter 23 converts the analog signal passed through the filter 22 into a digital signal. For example, the range from 0 to 5 V is replaced with an integer from 0 to 255 (8 bits). Case).

 The magnification determining section 24 has an internal structure as shown in FIG. That is, A /

A branch path is provided via a switch S to a line that transmits a signal in a through state from the D conversion section 23 to the contact switch 25, and a voltage comparison section 24a is connected in series with the branch path. And a control signal generator 24b. The switch S opens and closes based on a control signal from the setting unit 29, and closes a contact in the learning mode.

 Then, the voltage comparison unit 24a determines whether the received digital signal exceeds the output range of the 80 conversion unit 23, and if so, the control signal generation unit 24b. Command to decrease the current control signal by one step. Also, if the received digital signal is smaller than a predetermined value, a command is issued to increase the numerical value by one step from the current control signal.

This judgment is based on the waveform of the sensor output when the door is actually opened and closed in the learning mode, and when the door is opened and closed. That is, control is performed so that the peak of the waveform falls within a predetermined range. Therefore, for example, if you add a hold function, This is more preferable because it can recognize the peak of the waveform and determine whether the value is appropriate. Then, the control signal generator 24 b sends a control signal about the amplification factor to the amplifier 21.

 As shown in FIG. 7, the learning unit 26 includes a trigger switch S1, a waveform storage unit 26a, and a threshold value calculation unit 26b connected in series. The trigger switch S1 receives a trigger signal from the setting unit 29 and closes the switch. In other words, if the trigger signal is generated from the setting unit 29 simultaneously with the opening and closing of the door while the learning unit 26 is connected to the learning unit 26 by the contact point switch 25 (learning mode is selected), the output signal of the AZD conversion unit 23 ( (Digital signal) 1 Waveform storage unit 26 Stored in 6a. This digital signal is captured for a certain period of time or until a certain storage capacity is reached.

 Then, the threshold value calculation unit 26b calculates a threshold value required for determination from the stored digital signal. Various algorithms can be used for calculating the threshold. For example, the threshold can be calculated by the following calculation. That is, the average value Va and the peak value Vp of the waveform data stored in the waveform storage unit 26a are obtained, and the threshold value Vh can be obtained by substituting into the following equation.

 V h = (V p-V a) X 0.5 + V a

 Then, the output (threshold) of the extreme value calculation unit 26 b is sent to the output unit 28 and the determination unit 27 in the next stage. When the door is opened and when it is closed, the sensor output is reversed. At this time, a switch (not shown) (provided on the operation unit 29, etc.) is used to teach which operation is to be performed. The sensor output is reversed when the door is moved out of the room and opened, and when the door is opened by moving into the room. By teaching or the operation of either pre Me As described above, recognition can recognize either type from the waveform of the sensor output, and exceeds the threshold is larger than the threshold value determination algorithm (threshold accordingly Alternatively, it is also possible to automatically determine the car that recognizes that the threshold value has been exceeded when it is smaller, Of course, a switch for setting the door type may be provided in advance.

The determining unit 27 includes a storage unit 27a and a threshold comparing unit 27b as shown in FIG. The threshold value sent from the learning unit 26 is stored in the storage unit 27a. So Then, the threshold value comparing section 27b compares the value based on the sensor output with the threshold value, and outputs the result. That is, when the judgment section is selected by the contact switch 25 (selection to the judgment mode), the threshold value is first read from the storage section 27a, and the digital signal from the AZD converter 3 is sent to the threshold comparison section 27b. Then, the two are compared, and an abnormal signal is output when the digital signal exceeds the threshold, and a normal signal is output when the digital signal does not exceed the threshold. This determination result is sent to the output unit 28. This is the normal operation in the security mode.

 Further, in this embodiment, a non-security mode (set by the setting unit 29) is provided, and when the non-security mode is selected, an abnormality is output when the digital signal does not exceed a threshold for a certain period of time. In other cases, normal signals are output. In other words, security mode is used when no one can enter the room. Therefore, if there is a sudden change in the pressure, such as when the door is opened or closed, it is considered abnormal because there is a high possibility that a person has entered. This allows monitoring for the presence of intruders. On the other hand, the non-security mode is used when a person constantly enters and exits the room. In this case, since it is normal that there is a pressure change accompanying the opening and closing of the door, it is not abnormal if the opening and closing of the door is detected. In this non-security mode, the door is opened and closed, and the sensor output normally changes. Therefore, if the pressure change does not change for a certain period of time, the pressure sensor fails or the pressure sensor is covered by the lid. It can be estimated that there has been an obstacle such as Therefore, an error is output when the threshold is not exceeded for a certain period of time. This allows self-diagnosis.

 The output unit 28 includes a threshold value display unit 28a and an LED display unit 28b as shown in FIG. The threshold numerical value display section 28a displays the threshold value calculated by the learning section 26 as a numerical value.The display method is, for example, displaying the numerical value itself on a liquid crystal display or arranging a large number of LEDs. May be turned on by an amount corresponding to the numerical value of the threshold. In addition, the LED display section 28b turns on the green LED when a normal signal is sent from the determination section 27, and turns on the red LED when an abnormal signal is sent.

As shown in Fig. 10, the setting unit 29 includes a cut-off frequency setting unit 29a, a learning Z judgment switch SWa29b, a security Z non-security switch SW29c, a trigger signal generation unit 29d, and the like. Preparation You. The cut-off frequency setting section 29a sets the cut-off frequency of the filter section 22 and is input as a numerical value. This numerical value may be input, for example, by a keyboard dial.

 The learning Z determination switch SW 29 b is a switch for selecting the learning or determination of the contact of the contact switch 25. The learning mode is connected to the learning unit 26 when the learning mode is set, and the determination unit 2 is set when the determination mode is set. 7 is connected.

 Security / non-security switching SW 29c is connected to the determination unit 27, and a determination algorithm is selected. In other words, it is considered abnormal if the threshold value is exceeded for crime prevention and abnormal if the threshold value is not exceeded for a certain period of time if non-crime prevention.

 The trigger signal generation unit 29 d is connected to the learning unit 26 and generates a trigger signal for starting learning. The trigger signal may be generated by a button or a pulse signal may be sent from outside. Then, upon receiving this trigger signal, the switch S of the learning section 26 is closed for a certain period.

 FIG. 11 shows an example of a system for monitoring the opening and closing of a door using the above-described pressure sensor. The system of the present invention may include not only one pressure sensor as described in FIG. 3 but also a plurality (two in this example) as shown in FIG. By installing a plurality of sensors in this way, it becomes possible to recognize which of the plurality of doors has been opened or closed.

 That is, as shown in the figure, room 17 is provided with three doors (A, B, C), and the first sensor 10a and the second sensor 10b are placed at arbitrary positions in the room. Provided. Since the sensors 10a and 10b are set apart from each other by a predetermined distance, the distance from the door A or the door C to the sensors 10a and 10b is different. The distance from door B is the same. Further, each of the doors A, B, and C is of a rotating type, and is of a type that opens the door by rotating out of the room 17.

In the illustrated example, only the first sensor 10a side is arranged so as to be hidden behind the partition wall 17, but this does not affect the detection sensitivity whether or not the partition wall 19 is provided. Without giving, it is described in order to explain that it may be installed in the room 17 in an exposed state like the second sensor 10b. Therefore, in actual installation, each sensor May be installed behind a partition wall, or both sensors may be exposed.

 With the above configuration, when one of the doors is opened, the pressure in the room decreases, and the sensor output decreases.On the contrary, when the door is closed, the pressure in the room increases, so the sensor pressure increases. The output rises. In other words, if the sensor output is increasing in pressure, as shown in Fig. 12A, it can be determined that the door is closed, and if the sensor output is decreasing in pressure, as shown in Fig. 12B, it is determined that the door has been opened. it can. In this case, since the two sensors output the same result, the accuracy of the determination result as to whether or not the door is opened and closed and which operation has been performed is improved without erroneous detection. The change in sensor output that accompanies opening and closing the door varies with the transmission time of the pressure change depending on the distance from the door, so the sensor closer to the door responds faster. In other words, as shown in Figs. 12A and 12B, a time lag occurs when the waveform is generated when the door is opened and closed.

 Therefore, it is possible to recognize which door has been opened based on which sensor has detected the pressure fluctuation accompanying the opening and closing of the door first. That is, as shown in FIG. 13, when the first sensor 10 a detects first, it can be determined that the door A located on the first sensor 10 a side has opened and closed, and Because of the pressure increase, it can be determined that door A was closed.

 Similarly, as shown in FIG. 14, when the second sensor 10b detects first, it can be determined that the door C is closed. Furthermore, as shown in FIG. 15, both sensors 10 a,

If 10b is detected almost simultaneously, it can be determined that door B has been closed. Of course, in the case of a downwardly convex waveform in each waveform diagram, it can be determined that the corresponding door is opened.

Also, as shown in Fig. 16, when each of the doors A, B, and C is a slide type, there is little air inflow and outflow due to the movement of the doors, so that the pressure change is small.部屋 However, as shown in the figure, a part of room 17 has an opening 17a, and when gas flows in or out of it, the door is opened and closed. Then, since the pressure changes, the opening and closing of the door can be detected according to the same principle as above. In other words, if gas is flowing in from the opening 17a, opening the door opens The pressure drops as the body escapes, and the pressure rises as the door closes and returns. When gas flows out of the opening 17a, the opposite phenomenon occurs. The system configuration for detecting the opening and closing of the door as described above can be achieved by, for example, a block diagram as shown in FIG. That is, the outputs of both sensors 10a and 10b installed at predetermined positions in the room are connected to the signal processing circuits 20a and 2Ob, respectively. The signal processing circuit used here can have substantially the same configuration as the signal processing circuit 20 shown in FIG. The difference is that a function to output the output (judgment result) of the judgment unit 27 to the outside is provided. That is, the output of the determination unit 27 in each of the signal processing circuits 20a and 20b is provided to the overall determination unit 30. Then, the comprehensive judgment section 30 recognizes which sensor has received the detection signal earlier (or the same) by using a built-in timer or the like or forming an appropriate logic circuit. In addition to determining whether the door has been opened and closed, the operation of the door (opened or closed) is also determined from the direction of the waveform, and the determination result is sent to the output unit 31 so that a predetermined alarm is output. As the output mode of the output unit 31, various types such as sound and light can be used.

 As described above, the pressure sensor according to the present invention detects the differential pressure by making the pressure responsiveness of the reference pressure side different from the pressure responsiveness of the pressure receiving side. The operating status of whether the door is open or closed can be recognized, and there are few restrictions on the installation position of the sensor, and it can be used as a sensor that is hard to find from outside that the sensor is installed.

Claims

The scope of the claims 1. A pressure sensor that detects a pressure difference between a pressure receiving side and a reference pressure side,  A pressure sensor including a device for making the pressure responsiveness of the pressure receiving side different from that of the reference pressure side. 2. The pressure sensor according to claim 1, wherein the device is a filter provided at least on the reference pressure side and serving as a gas passage resistance.  3. The pressure sensor according to claim 1, wherein the device is a closed space forming member provided on the reference pressure side.  4. The pressure sensor according to claim 3, wherein the closed space forming member has a minute hole.  5. The pressure-receiving side detects the pressure in the room having the door, and the reference pressure side receives the same pressure as the pressure in the room,  The pressure sensor according to any one of claims 1 to 4, wherein a pressure change due to opening and closing of the door is detected using a difference in pressure responsiveness between the pressure receiving side and the reference pressure side.  6. A plurality of pressure sensors, each of the pressure sensors having a device for differentiating the pressure response between the pressure receiving side and the reference pressure side, and detecting a pressure difference between the pressure receiving side and the reference pressure side, The plurality of pressure sensors are installed in a room having a plurality of doors to be monitored, and determine which of the plurality of doors has been opened or closed based on a shift in sensor output of the plurality of pressure sensors. A door opening / closing monitoring system further comprising a determination unit. Claims of amendment  [October 01, 1999 (0.1.109.99) Accepted by the International Bureau: Claim 1 has been amended; other claims remain unchanged. (1 page)]  1. (after correction) a pressure sensor for detecting a pressure difference between the pressure receiving side and the reference pressure side, including a device for making the pressure response different, wherein the pressure receiving side and the reference pressure side are arranged in the same gas; A pressure sensor that has the same pressure in a steady state with no flow.  2. The pressure sensor according to claim 1, wherein the device is a filter provided at least on the reference pressure side and serving as a gas passage resistance.  3. The pressure sensor according to claim 1, wherein the device is a closed space forming member provided on the reference pressure side.  4. The pressure sensor according to claim 3, wherein the closed space forming member has a minute hole.  5. The pressure-receiving side detects the pressure in the room having the door, and the reference pressure side receives the same pressure as the pressure in the room,  The pressure sensor according to any one of claims 1 to 4, wherein a pressure change due to opening and closing of the door is detected using a difference in pressure responsiveness between the pressure receiving side and the reference pressure side.  6. A plurality of pressure sensors, each of the pressure sensors having a device for differentiating the pressure response between the pressure receiving side and the reference pressure side, and detecting a pressure difference between the pressure receiving side and the reference pressure side,  The plurality of pressure sensors are installed in a room having a plurality of doors to be monitored, and determine which of the plurality of doors has been opened or closed based on a shift in sensor output of the plurality of pressure sensors. A door opening / closing monitoring system further comprising a determination unit. 16  Amended paper (Article 19 of the Convention)